Search

Navigation

Moodle VPL Tutorials

From DftWiki

The tutorials below are intended for instructors teaching programming languages, and interested in setting up Moodle VPL modules to automatically test student programs.
The modules are listed in chronological order, most recent at the end. Because VPL is a complex system to master, the
early tutorials may not be built using the best approach, but provide functionality. The later modules use more sophisticated features of VPL.
Feel freel to send me your own modules or discoveries, at dthiebaut@smith.edu, and I will be happy to include them here.

Setting up a VPL module for Python

This tutorial provides rough directions for setting up two virtual servers that will host Moodle on one of them, and the VPL jail server on the other. This setup is used by the tutorials below on the use of VPL to test student programs.

This tutorial illustrates how to setup VPL to test a simple Python 3 program that receives 3 numbers from the console and prints the smallest of the 3. The program is tested 3 times, with 3 different sets of input numbers.

This tutorial shows the settings for a VPL activity that would test a Python program that plays the game of Rock-Paper-Scissors. The program tested is expected to get its input as pairs of letters (PP, RS, PS, etc), indicates the winner of each round, and stops when one player is 3 points above the other.

This tutorial illustrates how to setup a VPL activity that tests a student program that reads a text file, modifies it, and stores the new content back in the original file. This requires an additional python program that sets up the environment for the first one to run, provides it the information it needs, and captures its output.

This tutorial illustrates how to setup a VPL activity that tests a student program that asks the user for an integer and then prints a 2D chessboard (alternating black & white cells) with that dimension. The size of a cell is a 3x3 character on the screen.

This tutorial illustrates the setting of a VPL activity that evaluates a 2-class Java project that gets its input from a data file. The project is tested with 4 different data files; one provided by the students, 3 provided by the instructor.

This VPL module tests two Java classes, one inherited from the other. The test checks that one class does not access directly a member array of the super class (look for presence of [ ] brackets in code). Different grades are given depending on various stages of success.

This VPL module tests a data structure provided by the student using a class provided by the instructor. The instructor class tests various methods. The grade is proportional to the number of correct output lines.

This VPL module tests how a program uses exceptions to parse a simple text file containing numbers. The vpl_evaluate.sh script generates 3 tests, and runs through all 3 of them. Vpl_evaluate.sh skips non digits and non minus characters when comparing the output of the submitted program to the expected output.

This VPL module tests a function in the student program and calls it several times to see if it performs correctly. The _start label of the student program is invalidated, and the student program is linked with a test program that calls the student function as an extern.

This VPL module tests a Java program and verify that its execution is greater than some predefined amount of time. Otherwise the program may be short-circuiting the execution and outputting a preprocessed answer.

This VPL module uses a Java test program that energizes the student's submitted class, activating various methods, and generates OK or FAIL strings for each test given. The vpl_evaluate.sh script simply counts the # of OK strings generated and gives grade proportional to it.

This VPL module requires the student to submit a program that contains only global assembly language functions. The module uses a test program in assembly that calls the functions with a given set of parameters, and tests whether the returned values are correct or not. The test program also verifies that none of the Pentium registers are modified. The testing script also ensures that the student program uses recursion for his/her solution.

This VPL module is written mostly in Python. vpl_evaluates simply calls a python program that tests the student's python code. The python test first attempts to run the student program as a subprocess to catch possible errors or crash. If this is successful, then the student code is imported and run, with its stdin and stdout redirected from and to files controlled by the test program.

This setup tests a bash script submitted by students. The script acts as a teller machine, getting an integer on the command line and printing 4 integers out, corresponding to the number of $20-bills, number of $10-bills, number of $5-bills, and number of $1-bills.

This setup tests a recursive program in assembly (binary search) that may time-out (possibly because of weird recursive coding.) The evaluate script will abort if the program takes longer than a specified amount of time. This uses a bash script for vpl_evaluate.sh and vpl_run.sh.

This setup tests a C program that is supposed to replicate some of the functionality of the Linux grep command. In particular, the C program should get its input from the command line and support the "-i" switch, for case-insensitive searching.